1. Field of the Invention
The present invention relates generally to a high pressure multi-stage pump which is especially adapted for pumping feedwater and the like, and wherein at each stage a differential pressure is developed by a regenerative turbine impeller.
2. Description of the Prior Art
A conventional high pressure regenerative pump comprises a main casing body, end bells, a shaft, an impeller at each stage, and liners at the opposide sides of each impeller.
Heretofore, interconnecting passages and suction and discharge connections have been integral with the main casing body, while the shaft bearing holders have been integral with the end bells (bearing brackets). As a consequence, the casing body and end bells have been of intricate design requiring complicated castings and machining to precise tolerances, and each variation in the number of stages required a new casting. Moreover, axial adjustment of the shaft, the impellers and the liners has been difficult; and excessive wear of the impellers and liners has been experienced. Also, replacement of end bearings and seals has required disconnection of the pump from the associated suction and discharge piping, and disassembly of the end bells. Additionally, coupling of the suction and discharge connections to suction and discharge piping, and decoupling of the pump, have not been as convenient as might be desired. Finally, primarily because of impeller positioning problems, high pressure regenerative pumps have been limited to no more than two stages.